In the United States, it is estimated that in 2008 approximately 1.2 million people will suffer a new or recurrent myocardial infarction (MI). Recently, tissue engineering cardiac patch has attracted research interests to repair injured heart and restore cardiac function. However, fabrication of 3D porous scaffolds that are thoroughly reseeded with cells remains a challenge for making a viable thick cardiac patch. We hypothesize that (i) decellularized porcine myocardium scaffold preserve natural ultrastructural, mechanical, and compositional cues for cardiac tissue regeneration and (ii) the 3D porous ECM structure and vasculature template would provide optimal microenvironments for stem cell reseeding, cardiomyocyte differentiate, and angiogenesis. A novel bioreactor that provides coordinated mechanical and electrical stimulations, along with biochemical cues, will be developed to facilitate in vitro conditioning of tissue constructs. Furthermore, different from approaches solely relying on expensive, time consuming, and trial-and-error animal experiments, we propose to use in vitro bioengineering assessments as quality control for the engineered patches. In this project, we will (1) develop the optimal decellularization protocol for porcine myocardium to generate natural 3D scaffold with interconnected porous network, (2) facilitate mesenchymal stem cell differentiation via in vitro conditioning using a bioreactor that provides coordinated mechanical and electrical stimulations, and (3) optimize electrophysiological and mechanical properties of the engineered cardiac patches. The hopes and expectations are that our novel approach will ultimately impact thousands of patients who are suffering myocardial infarction. Furthermore, knowledge gained from the proposed research would help us better understand fundamental bioengineering in the development of thick cardiac patch and benefit future exploration of whole-heart reconstruction using the scaffold template from large animal heart. PUBLIC HEALTH RELEVANCE: Each year, approximately one million Americans suffer myocardial infarctions (MIs) with a 10% in-hospital mortality rate. Cardiac patch repair is a promising treatment option for MI patients. In this project, we propose to fabricate a viable thick cardiac patch with decellularized porcine myocardial scaffold and bone marrow mesenchymal stem cells, via the assistance of a novel bioreactor that provides coordinated mechanical and electrical stimulations. The knowledge gained from our study and clinical product that we envision would benefit thousands of patients who are suffering MIs.